Last years run was:

Truck at apx. 12,000 miles
No stock run this time
PREDATOR SET ON THE 85HP TUNE / 389 RWHP - 662 FT/LBS (ENGINE hp 456)
PREDATOR SET ON THE 120HP TUNE / 434 RWHP - 729 FT/LBS ENGINE hp 508)

The only difference this year was I added Amsoil SAE 15W-40 Synthetic Blend Diesel Oil and Amsoil Synthetic Automatic Transmission Fluid / Trans-Go Kit and the S&B Intake System:

Truck at apx. 27,400 miles
Stock: 355 RWHP - 607 FT/LBS (ENGINE hp 407)
PREDATOR SET ON THE 85HP TUNE / 423 RWHP - 709 FT/LBS (ENGINE hp 483)
PREDATOR SET ON THE 120HP TUNE / 458 RWHP - 754 FT/LBS (ENGINE hp 523)

Gains from last years numbers:

PREDATOR SET ON THE 85HP TUNE / 34 RWHP - 47 FT/LBS
PREDATOR SET ON THE 120HP TUNE / 24 RWHP - 25 FT/LBS

 

Good numbers. I'd say you got most of your gain from the shift kit.

 

Possibly, but I know some had to do with the S&B Intake System.

 

I think you might be surprised how good the stock GM airfilter flows.. There is a full laboratory study on the different air filers and the systems they go with, and it shows the stock GM filter with THE BEST FILTRATION and THE MOST CFM... This is the main reason why most GM diesel owners just did a simple air box mod to help use it all.. So Im betting most of your gains came from the shift kit as well... Those are some nice numbers..!

 

synthetic oils help too